<h2 mat-dialog-title>Enter expense details:</h2>
<p class="error" *ngIf="shouldShowError">{{error}}</p>
<mat-dialog-content>
  <mat-form-field>
    <mat-select placeholder="Category" [(ngModel)]="expenseType" required>
      <mat-option *ngFor="let t of types" [value]="t">
        {{t}}
      </mat-option>
    </mat-select>
  </mat-form-field>
  <mat-form-field>
    <input matInput placeholder="Amount" [(ngModel)]="amount" required>
  </mat-form-field>
</mat-dialog-content>
<mat-dialog-actions>
  <button mat-button (click)="cancel()">Cancel</button>
  <button mat-button (click)="submit()" [disabled]="!isFormValid()">Add</button>
</mat-dialog-actions>
